Procedure for Heating Steering Components to Facilitate Field Disassembly of Pin-Cylinders and Ball Studs on Large Mining Trucks {0679, 0732, 4006, 4016, 4251, 4300, 4305, 7200} Caterpillar

Off-Highway Truck/Tractor

789 (S/N: 9ZC1-UP)

789B (S/N: 7EK1-UP)

789C (S/N: 2BW1-UP)

789D (S/N: SPD1-UP; SHH1-UP; TWP1-UP)

793 (S/N: 3SJ1-UP)

793B (S/N: 1HL1-UP)

793C (S/N: CBR1-UP; 4AR1-UP; ATY1-UP; 4GZ1-1)

793D (S/N: FDB1-UP)

793F (S/N: SND1-UP; SSP1-UP; SXP1-UP; D3T1-UP; RBT1-UP)

793F AC (S/N: EMD1-UP)

794 AC (S/N: MT51-UP)

795F AC (S/N: ERM1-UP)

795FAC XQ (S/N: SNT1-UP)

797 (S/N: 5YW1-UP)

797B (S/N: JSM1-UP)

797F (S/N: LAJ1-UP; WSP1-UP; LTZ1-UP)

Introduction

This Special Instruction provides general guidelines for heating steering components to facilitate field disassembly of pin-cylinders and ball studs. Heating of steering components should only be implemented after component disassembly utilizing the 524-5362 Hydraulic Hammer Gp or 524-9370 Hydraulic Hammer Gp has been attempted and troubleshooting procedure identified in Tool Operating Manual, M0080743, "Ball Stud Breaker (524-5362 Hammer Group)" has been followed. Specific areas of heat application covered in this Special Instruction include: steering arm, steering box and center arm.

The purpose of heating the steering component at the ball stud and/or pin-cylinder juncture is to create a small amount of thermal growth in the tapered bore. This growth facilitates a minimal and temporary reduction in fit between the tapered bore of the steering arm/steering box/center arm and the tapered portion of the ball stud/pin-cylinder.

Using controlled application of heat as hereby identified and the immediate application of impact force from the 524-5362 Hydraulic Hammer Gp or 524-9370 Hydraulic Hammer Gp, stuck/stubborn ball studs and pin-cylinders may be easily separated.

Do not perform any procedure in this Special Instruction until you have read the information and you understand the information.

Note: Heating of steering components should only be implemented after component disassembly utilizing the 524-5362 Hydraulic Hammer Gp or 524-9370 Hydraulic Hammer Gp. For additional information refer to the troubleshooting section of Tool Operating Manual, M0080743, "Ball Stud Breaker (524-5362 Hammer Group)".

Safety Section

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Do not operate or work on this product unless you have read and understood the instruction and warnings in the relevant Operation and Maintenance Manuals and relevant service literature. Failure to follow the instructions or heed the warnings could result in injury or death. Proper care is your responsibility.

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Failure to follow all safety guidelines prescribed in this document and by governing authorities and regulatory agencies may result in severe injury or death of personnel or machine damage.

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When removing a major component or attachment, ensure that it is properly blocked or secured before removing mounting hardware. An assembly that is disconnected without proper blocking may shift or fall, resulting in serious injury or death of personnel or machine damage.

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Personal injury or death can result from improper maintenance procedures. To avoid injury or death, follow the procedures exactly as stated below.

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Personal injury can result from improper handling of chemicals. Make sure you use all the necessary protective equipment required to do the job. Make sure that you read and understand all directions and hazards described on the labels and material safety data sheet of any chemical that is used. Observe all safety precautions recommended by the chemical manufacturer for handling, storage, and disposal of chemicals.

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Climbing equipment may be required to access this service point. Refer to the Operation and Maintenance Manual, "Mounting and Dismounting" topic for safety information.

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Before servicing/performing maintenance on the machine, electrical power must be physically disconnected; battery plugs must be disconnected from the batteries, or the trailing cable must be unplugged, and warning tags and padlocks shall be applied by a certified electrician. Certified electricians shall perform or direct any electrical work, including any energized testing, repair work in controllers, motors, or other approved compartments, and shall insure that all compartments are properly closed and inspected prior to re-energization. All applicable lock out and tag out procedures must be followed.

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Do not operate the machine if any guards or covers are missing or inadequately secured. Personnel could be seriously injured or machine damage may occur.

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Observe the safe working load limits of all lifting and blocking devices and keep a safe distance from suspended/blocked loads. Personnel may be seriously injured or killed by falling loads.

Required Tools

Prework

1. Verify the items identified in the troubleshooting procedure in Tool Operating Manual, M0080743, "Ball Stud Breaker (524-5362 Hammer Group)" have been reviewed.

2. Thoroughly clean the steering component of any dirt and oil/grease.

3. Ensure that tooling C is installed on the ball stud or pin-cylinder in accordance with Tool Operating Manual, M0080743, "Ball Stud Breaker (524-5362 Hammer Group)" and Tool Operating Manual, M0083627, "Pump Group (HPU) 524-5342 (460 V/60 Hz/3 Phase), 524-5343 (230 V/60 Hz/3 Phase), 524-5344 (415 V/50 Hz/3 Phase), 524-5345 (380 V/50 Hz/3 Phase), 524-5346 (600 V/60Hz/3 Phase)".

Heating Process

The purpose of heating the steering component at the ball stud and/or pin-cylinder juncture is to create a small amount of thermal growth in the tapered bore. This growth facilitates a minimal and temporary reduction in fit between the tapered bore of the steering arm/steering box/center arm and the tapered portion of the ball stud/pin-cylinder.

In order to achieve the benefits of the thermal growth, heat must be applied in a quick and focused manner. Excessive heating or soaking of the joint will eliminate the benefits of thermal growth and may cause damage to the steering component. It is critical that the recommended times and temperatures are not exceeded.

Note: The maximum component temperature while performing the heating process should not exceed 350° C (662° F). Heating of components in excess of the maximum specified temperature may result in permanent component damage.

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Illustration 1	g06331379
Steering positions : 789, 793, 797 Location of joints in steering

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Illustration 2	g06331392
Steering positions : 795 Location of joints in steering

1. Identify the steering position requiring service. Refer to Illustration 1 and Illustration 2.

2. Identify the appropriate layout location and heating procedure from Section "Layout Locations and Heating Procedure".

   Note: It is recommended that one technician performs the heating, while a second technicians monitors temperature and time intervals. The technician checking temperature should advise the technician operating the torch of appropriate times to start/stop, switch sides (as applicable) and temperatures.

   Note: Heat must penetrate the steering component in a quick and targeted manner in order to achieve the appropriate expansion required to free stuck/stubborn pin-cylinders/ball joints. Excessive heating or “soaking” of the steering component will cause the pin-cylinder/ball joint to thermally expand at an equal rate. This will negate the desired effect from the heating process and can result in irreversible damage to the steering component material.

3. Utilize tooling (T2) to heat the steering component in accordance with the defined heating process. Tooling (T1) should be used to monitor the temperature of the steering component immediately after the torch passes over the defined heating zone. The maximum temperature for all positions is 350° C (662° F).

4. Immediately following the heating process, strike the joint using tooling (T3).

   Separation should occur within the first 10-15 seconds of impact. If the joint does not separate, allow the steering arm, steering box or center arm to cool to ambient temperature, then reapply heat in accordance with the outlined process and strike with tooling (T3).

   Note: Refer to your machines Disassembly and Assembly manuals for appropriate procedures.

Layout Locations and Heating Procedure

Position 1

Illustration 3	g06331652
(A) 75 mm (3.0 inch)

Illustration 4	g06331656

Mark one window 75 mm (3.0 inch) in height from point (C) to (D) as shown in Illustration 3 and Illustration 4.

1. Beginning at the upper portion of the window, hold the torch tip approximately 25 mm (1.0 inch) from the surface.

2. Move the torch tip from point (C) to point (D) in repeating strokes. Repeat process working from top to bottom.

3. Heat approximately for 3-5 minutes or until maximum temperature is reached.

   Note: Continuously monitor temperature while heating, maximum temperature not to exceed 350° C (662° F).

Position 2

Illustration 5	g06331662
(D) 125 mm (4.9 inch) (E) 75 mm (2.9 inch)

Illustration 6	g06331665

Mark two windows 125 mm (4.9 inch) long by 75 mm (2.9 inch) in height from points (F) to (G) and (H) to (J) as shown in Illustration 5 and Illustration 6.

1. Beginning with the upper portion of the inner window, hold the torch tip approximately 25 mm (1.0 inch) from the surface.

2. Move the torch tip from point (F) to point (G) in repeating strokes. Repeat process working from top to bottom. Heat approximately for 1 minute.

3. Switch to the outboard side of the steering arm.

4. Starting from the upper porting of the window, heat from point (H) to point (J) in repeating strokes. Repeat process working from top to bottom, heating for approximately 1 minute.

5. Continue alternating sides every 1 minute, for a maximum time period of 4-5 minutes or until maximum temperature is reached.

   Note: Continuously monitor temperature while heating, maximum temperature not to exceed 350° C (662° F).

Position 3

Illustration 7	g06331674
(K) 75 mm (2.9 inch)

Illustration 8	g06331675

Mark a window 75 mm (2.9 inch) in height from points (L) and (M) in 789 and 793 Off-Highway Trucks as shown in Illustration 7 and Illustration 8.

1. Hold the torch tip approximately 25 mm (1.0 inch) from the surface.

2. Move the torch tip from point (L) to point (M) in repeating strokes. Repeat process working from top to bottom.

3. Heat approximately for 2-3 minutes or until maximum temperature is reached.

   Note: Continuously monitor temperature while heating, maximum temperature not to exceed 350° C (662° F).

Position 4

Illustration 9	g06331681

Mark a centerline along the steering box "lower tab" feature in 795 and 797 Off-Highway Trucks as shown in Illustration 9.

1. Hold the torch tip approximately 25 mm (1.0 inch) from the surface, centered on the lower steering box casting feature.

2. Move the torch tip from point (N) to point (P) in repeating strokes. Repeat process working from top to bottom.

3. Heat approximately for 2-3 minutes or until maximum temperature is reached.

   Note: Continuously monitor temperature while heating, maximum temperature not to exceed 350° C (662° F).

Position 5

Illustration 10	g06331688
(R) 75 mm (2.9 inch)

Illustration 11	g06331689

Mark a box 75 mm (2.9 inch) in height from point (S) to point (T) as shown in Illustration 10 and Illustration 11.

1. Beginning at the upper portion of the window, hold the torch tip approximately 25 mm (1.0 inch) from the surface.

2. Move the torch tip from point (S) to point (T) in repeating strokes. Repeat process working from top to bottom.

3. Heat approximately for 2-3 minutes or until maximum temperature is reached.

   Note: Continuously monitor temperature while heating, maximum temperature not to exceed 350° C (662° F).